I had a similar truck (2004 model) which has a 12,000 lb. tow rating. Your REAL weight limit for a 3/4 ton truck will be the available payload of the truck as it relates to the PIN weight. YOu mentioned SAFELY towing which indicates you need to watch SAFETY related limits which are GVWR and GAWR of the truck (both located on the DOT SAFETY plate on your door post (required by federal law). Max trailer weight is a warranty issue and it's not likely you have any warranty left on a 2001 model truck. That's the REASON it is not on the safety plate.
Good luck / Skip